Toray Industries, Inc.

Koichi Aizu

Joji Funakoshi

Tomoki Tamura

Keiichi Ishio

Masaki Nakano

Fumito Oshima

Takashi Kawamoto

Provided herein is a method for producing an acrylonitrile based fiber bundle by dry-jet wet spinning technique that serves to allow a high-grade, high-quality acrylonitrile based fiber bundle to be produced stably even if the traveling speed of the coagulated fibers is increased or the number of spinneret discharge holes is maximized in an attempt to enhance the production efficiency. The production method for an acrylonitrile based fiber bundle is characterized by first extruding a spinning dope solution through a plurality of discharge holes in a spinneret, then allowing the spinning dope solution to run downward into a coagulation bath liquid stored in a coagulation bath to form coagulated fibers, turning the coagulated fibers upward on a direction changing guide part located in the coagulation bath liquid below the spinneret, and pulling them out of the coagulation bath liquid, wherein certain requirements are met.

Acrylonitrile-based fiber bundle manufacturing method

Provided is a method for manufacturing a combined yarn bundle including the steps of bringing the two or more carbon fiber precursor yarns which travel approximately parallel to one another into contact with a first roller at a wrap angle of 20&#xb0; or more. Then, the two or more carbon fiber precursor yarns are split into two and brought into contact with a pair of second rollers, so that the carbon fiber precursor yarns are rotated approximately 90&#xb0; between the first roller and the pair of second rollers. Next, the carbon fiber precursor yarns delivered from one second roller are brought into contact with a third front roller and a third rear roller, and the carbon fiber precursor yarns delivered from the other second roller are brought into contact with the third rear roller without bringing them into contact with the third front roller, so that these carbon fiber precursor yarns are combined on the third rear roller. Thereafter, the carbon fiber precursor yarns delivered from the third rear roller are brought into contact with a fourth roller to obtain a combined yarn bundle. A ratio of a distance L between axes of the first roller and of the pair of second rollers to a yarn width W of the carbon fiber precursor yarn on the first roller, L/W, is 18 or more and a tension of the combined yarn bundle after delivered from the fourth roller is 0.11 cN/dtex or more.

Method for manufacturing combined yarn bundle, and method for manufacturing carbon fiber in which resulting combined yarn bundle is used (as amended)

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Ehime, Japan

Koichi Aizu